Various types of connections for two pipes which permit a degree of flexibility of the connection are known. Such flexibility is required, for example, when exhaust gases are carried by the pipes. The connections, of course, must be tight to prevent the escape of any of the fluids, typically exhaust gases, within the pipes. The pipes will change dimension upon carrying hot exhaust gases and, for example, upon reverting again to ambient temperature. Additionally, the pipes may be subjected to external twisting, that is torsional, lateral, and other forces which may be caused by differential expansion and contraction of components under heating and cooling conditions, or under conditions of vibration or other stresses being applied.
A known pipe connection which permits some change in dimensional orientation of two pipes can be formed by a bellow, The bellows may have connecting elements located outside of the bellows, which have the tendency to hold the ends of the pipes in a predetermined centered position with respect to each other, the bellows, however, permitting limited change. The arrangement is expensive and space-consuming. The bellows itself is used for sealing and to permit a degree of flexibility. Torsional forces, however, cannot usually be accepted by the bellows, since a bellows is not suitable to accept torsion or twisting forces; if such forces are applied to the bellows, it will have the tendency to tear and thus the sealing integrity thereof is impaired. Bellows are expensive, and to permit a reasonable degree of longitudinal change, require a substantially long axial dimension. Only if the bellows are comparatively is it possible to consider a reasonable lifetime for such a connection without damage to the sealing capability of the bellows.
The bellows, when used, are usually connected to the pipes by flanges. The flanges additionally increase the cost of such a connection, and are space-consuming. The size of such connection elements also determines the length of the bellows which is used.
Other connecting arrangements for pipes have been proposed, each having specific disadvantages, based on the individual construction. For example, it is possible to connect two ends of pipes simply by using a corrugated pipe structure. To accomodate a reasonable degree of change, it is necessary to utilize a corrugated element of comparatively long dimension. In those installations in which it is necessary that the connection is stiff with respect to bending forces, for example if the connection is to be self-supporting without additional hangers, torsional forces or torsional or twisting movement cannot be accepted. The damping characteristic of such connections is poor and the spring characteristic of the corrugated element itself is linear.
It has been proposed to couple two ends of pipes by providing a ball-and-socket arrangement of spherical shape, similar to a ball joint, and clamping the ends of the pipes together by compression springs. The axial construction of such an arrangement is comparatively small. The construction, however, does not permit axial movement or lateral shifting of the ends of the pipes with respect to each other. The compression springs compressing the elements of the ball-and-socket joint together required substantial space in radial direction. The construction has another disadvantage which is economic--the manufacture of spherical contours is expensive and additionally is subject to excessive wear. Additionally, the connection, in use, is apt to be noisy.